Hitherto, it has been known that phenolic compounds etc. can be macromolecularized by utilizing an enzyme such as laccase or polyphenol oxidase produced by Basidiomycotina or Deuteromycotina (Journal of Biotechnology, 13, 229-241, 1990 and etc. so on). However, the laccases or polyphenol oxidases produced by fungi have their optimal reaction pH in the acidic region so that the reaction must be carried out in pH region ranging from acidic to neutral in order to catalyze or accelerate the macromolecularization reaction utilizing these enzymes and in addition, the rate of the macromolecularization reaction is not high enough. Also, the natural organic compounds with which these enzymes react are mainly polyphenolic compounds and, hence, the reaction must be carried out in the pH region ranging from acidic to neutral because the optimal reaction pH of the enzyme is in the acidic region despite the fact that the polyphenolic compounds have solubilities which decrease in the pH region from acidic to neutral, resulting in a defect that it is impossible to efficiently macromolecularize polyphenolic compounds in high concentrations. Further, although many polyphenolic compounds are accelerated their autooxidation in the alkaline pH region, enzymatic oxidative macromolecularization has been carried out in the pH region ranging from acidic to neutral, resulting in a defect that the autooxidation cannot be utilized effectively.
Further, it has been known that phenolic compounds, etc. can be macromolecularized with bilirubin oxidase, too, and this reaction can be utilized in the macromolecularization of lignin and dying of cotton (WO95-01426, and JP-A-6-316874). However, in the prior art using bilirubin oxidase, the enzyme-catalytic macromolecularization of phenolic compounds, etc., is carried out in the pH region ranging from acidic to neutral and therefore the macromolecularization reaction rate is not sufficiently high or there is no description suggesting that the macromolecularization reaction of phenolic compounds is accelerated in the alkaline pH region by bilirubin oxidase.